Peter, after a little searching I have found a c 1970 Reynolds catalogue, which gives gauges foir different frame sets. Bill Hurlow's choice is remarkably close to a 531 Professional tube set. Bill's tube thicknesses are: seat tube 21/24: .81mm/.55mm downtube 20/23: .91/.61mm top tube 22/24: .71/.55mm
So the stiffest tube is, as one would expect, the downtube. The plain lengths of the seat and top tube are the same with thicker butted sections for the more highly stressed seat tube. Ignoring the butted weight difference that makes the downtube roughly 10% heavier for a given length ---------------------------------------------------------------------------- ------- Norris also writes of builders selecting their tubes with lightness in mind. Bill Hurlow told me the tubes he would have used for my 1959 Hurlow time trial frame, which were 21/24 gauge seat tube, 20/23 gauge down tube, and 22/24 gauge top tube. Does anyone know just how much difference there was in weight between these different gauges?
Peter Brown, Lincolnshire, England ---------------------------------------------------------------------------- ------------------------ Back to dates of introduction I have another Reynolds catalogue that states '1930 "531" brand introduced' This is clearly incorrect and I suggest that all such statements should be treated with caution. A 1944 Cycling ad that I got from Mick Butler states: 1925-1929 Intensive development of special steels for cycle construction 1929 HM Steel introduced 1933 Light Alloy development 1935 531 Steel introduced
However, according to the following Reynolds history website HM was
introduced in 1924, and specifies cycle use. So, as with all research,
beware single source information and avoid categoric statements, unless you
enjoy being shot down. The only exception I would make to this rule is my
own birthdate and even then, I like to have my birth certificate on hand!
http://web.archive.org/
Nigel Land
North Lincs
UK